There is a good article on this subject in the Spring edition of Sedes Sapientiae by Bernard Lucien, a priest and theologian of the archdiocese of Vaduz (Sedes Sapientiae is the journal of the Fraternity of St Vincent Ferrer.) Fr Lucien distinguishes three ways in which the teaching authority either of the Pope or of the body of bishops with the Pope may be engaged:-

1. Full engagement. This means that a doctrine is taught directly or per se, and as bound up with revelation (either directly revealed or as in some other way necessarily linked to what is revealed). Such teaching is infallible and so must be definitively accepted.

2. Partial but authoritative engagement (‘merely authentic’). Again this means that a doctrine is taught directly or per se, but here no link with revelation is explicitly affirmed. This is what calls for ‘religious assent’, even though the possibility of error is not absolutely excluded.

3. Merely pedagogical and not authoritative engagement. This is found when a doctrine is not taught directly and per se, but is presented by way of introduction, explanation, argument, illustration or inference with regard to what is being taught directly. The author considers that this 3rd category, which he reckons is present to a large extent in Vatican II, has, as its proper response, ‘careful attention’ (l’attention docile) rather than adhesion of the mind as such.

The distinction between 2 and 3 seems to me useful, and not often made.

So with regard to Vatican II, he argues:

A. The faithful must begin by a ‘global adhesion’ to the council, which, however, does not mean begin by accepting it all as unquestionable, but rather accepting it all as an act of the supreme magisterium (against certain SSPX views which hold that John XXIII and Paul VI showed in certain remarks that they didn’t wish to exercise the magisterium), in such a way that the reception of individual points must depend on the mode of magisterial engagement at that point.

B. Statement such as ‘Vatican II was infallible’ or ‘Vatican II was not infallible’ or ‘Dignitatis Humanae [say] was, or was not, infallible’ are misguided. It is not the council as a whole or documents as a whole which should be qualified in this way, but particular statements of doctrine within each document, judged according to the criteria 1-3 mentioned above.

C. Vatican II should be held to be teaching infallibly whenever it directly teaches a doctrine and presents it as revealed or linked to revelation. Otherwise the Church would fail in its God-given task of keeping revealed truth undistorted.  The author considers that the central affirmation of Dignitatis Humanae – whatever it is! – is thus infallibly taught.

D. Vatican II teaches in a non-infallible way when it affirms a doctrine but does not affirm that this doctrine is revealed or linked to revelation. The author considers that the sacramental nature of the episcopacy is an example of such a teaching. This of course raises the question that Aelianus raised recently, of what the point is of such teaching.

E. Vatican II makes statements that do not as such require the assent of the faithful but rather their respectful attention. The author suggests that the ‘personalist’ philosophy by which the central affirmation of Dignitatis Humanae is supported may be an example.